A method for sampling a sulphur-containing solid product including supplying a gas flow comprising hydrogen sulphide, bringing the gas flow into contact with a solid reagent and reacting the solid reagent with the hydrogen sulphide contained in the gas flow, the reaction fixing the sulphur of the hydrogen sulphide by forming a sulphur-containing solid product which is different in color from the solid reagent, and recovering the sulphur-containing solid product. The invention also relates to a device suitable for the implementation of this method.